Questions about growth.
Find answers to some of the most common questions about growth hormone-related disorders and treatment. If you still have questions, and can’t find the answers on this website, be sure to ask your doctor.
Growth hormone therapy
Hormones are chemical messengers produced in one part of the body that travel to another part of the body to create some sort of change. Growth hormone is made in the pituitary gland, at the base of the brain, and is very important in helping children grow.
When growth hormone is released from the pituitary gland, it makes the liver release a second hormone called insulin-like growth factor-1 (IGF-1). Together, growth hormone and IGF-1 tell the bones, muscle, and many other organs and tissue to grow by adding more cells. The growth of the bones also requires bone cells to add minerals such as calcium and phosphate, which results in bones that are strong and long.
Growth Hormone Deficiency
A deficiency means there is not enough of something. Growth hormone deficiency means just that: your body is not making enough growth hormone.
Lack of treatment for growth hormone deficiency could result in a child being significantly shorter than they otherwise would be when they reach adulthood. Adults who are not treated for GHD may have changes in the body such as weakening of bones, decrease in amount of muscle, and increase in fat and cholesterol.
Usually an endocrinologist (a doctor who specializes in the study of the hormone system in your body) will be able to tell if you have growth hormone deficiency. The doctor will ask many questions about your health and growth history and about the health and growth history of your family. You will have a physical exam. The doctor may also order a growth hormone stimulation test, or "stim" test.
There are different types of growth hormone stimulation tests. Some are able to measure the level of growth hormone when it is at its highest, for example, after sleep or exercise, because both of these activities increase the level of growth hormone. Another type of test uses a medicine to make the pituitary gland release growth hormone. If the pituitary does not produce growth hormone in response to this "stimulation," it is a sign that the person has a deficiency.
There are several organizations dedicated to education, awareness, and advocacy for people with growth-related disorders. Take a look at the Patient Advocacy Groups.
The stimulation (“stim”) test
The pituitary gland produces growth hormone in different amounts at different times of the day. This makes it difficult to test the amount of growth hormone the pituitary gland is releasing with just one blood sample. So, endocrinologists perform what is called a stimulation test, or "stim" test, which uses a series of blood samples to get a more accurate picture.a There is no one approved method for stim testing, but here’s an example of what might occur (talk with your health care provider for specific information):
- Your child will be given an IV and the first blood sample will be taken.
- Then, the stimulating medicine will be given. Your child will be closely monitored for any side effects that may occur.
- Blood samples will be taken over the next few hours. Your child will be able to rest or do quiet activities during this time.
- When the last blood sample has been taken and the test is over, the IV will be removed.
- The doctor will communicate with you about when you’ll receive the results of the test and what the next steps will be.
aWith all medicines, there are benefits to using them; however, there may be side effects. The medicines used during the stim test may cause side effects. If you have any questions, ask your health care provider.
- Explain the test to your child, including why it’s being given. Talk about the IV. You may want to demonstrate on a doll. Your child’s doctor will likely recommend that he or she not eat and limit physical activity for 10-12 hours before the test, to avoid changing the results.
- Keep in mind that the test will take at least several hours and sometimes can take most of a day. You might consider bringing activities for yourself and your child to keep busy while you’re waiting.